Homocysteine levels in hypertensive patients with a history of cardiac or cerebral atherothrombotic events.

Hypertension is one of the most important risk factors for cardiovascular morbidity and mortality. Recently it has been suggested that the amino acid homocysteine contributes to this process. This study evaluates whether elevated plasma levels of homocysteine in hypertensive patients are associated with increased risk for cardiovascular events. Fifty hypertensive patients with a documented history of cerebral or cardiac events were age and gender matched to 50 hypertensive patients with no evidence of any cerebral or cardiac event. Demographic details, duration of hypertension, presence of other risk factors, and use of antihypertensive medications were recorded for each patient. Plasma levels of homocysteine were measured by high-performance liquid chromatography technology. The two groups had similar demographic parameters, with a mean age of 64.6 +/- 9.4 years. Patients with cardiovascular events were more likely to be past smokers and to have been treated with calcium antagonists, aspirin, and nitrates. Homocysteine levels were 12.1 +/- 5.8 micromol/L in those with documented cardiovascular disease and 11.1 +/- 4.7 micromol/L in those without (P = NS). Levels of plasma homocysteine were higher in those with hypercholesterolemia (P = .03) and in smokers, and tended to be lower in those who used beta-blockers, angiotensin converting enzyme (ACE) inhibitors, diuretics, and nitrates. Thus, hyperhomocysteinemia is not a feature of hypertensive patients with atherothrombotic events and there is no support for additive or synergistic effects between these two independent risk factors.

The effect of caffeine on ambulatory blood pressure in hypertensive patients.

Because the potential impact of habitual caffeine intake on blood pressure is a controversial issue, a study was carried out to explore the relationship between caffeine and various humoral factors that could account for a coffee-induced rise in blood pressure. Twenty-three hypertensive patients who refrained from caffeine for 2 to 3 weeks were given 250 mg oral caffeine powder dissolved in water. Blood pressure was recorded every 15 min by blood pressure monitor. Caffeine blood level, renin and endothelin were measured before and 1, 2, 3, and 6 h after caffeine intake. Urinary electrolytes and catecholamines were measured under caffeine influence (period I), and for the next 6 h (period II). A significant increase in systolic (P = .017) and diastolic blood pressure (P = .023) occurred in 13 subjects who were 58 +/- 10.4 years old. Nonresponders were younger (44.5 +/- 15.8 years). A statistically significant decrease in heart rate was seen during the first hour after caffeine intake in both responders (P = .008) and nonresponders (P = .004). Marked diuresis and natriuresis were observed during period I in both groups. Renin and endothelin levels were unchanged. Although chronic studies point to development of tolerance to long-term caffeine ingestion, acute studies like the one described are essential to obtain data on the immediate effects that can be of practical importance, especially in the elderly.